In recent years, the unit wiring racks used in computer systems have circuit boards mounted by insertion into the unit wiring rack with a panel as a lid. In this case, the input and output of electrical signals may be performed via a connector mounted on the panel and connected to the circuit board (front panel type).
FIG. 13 shows a plurality of panel circuit boards comprising a panel and a connector mounted on a circuit board, inserted into a unit wiring rack. When the storage space in the unit wiring rack is sufficiently large as shown in FIG. 13, large circuit boards can be used. In that case, because conventional circuit boards are large and the edges are long enough in the longitudinal direction of the panels, they were able to be assembled with the connecting portion between the ejector and the circuit board and the connecting portion between the connector and the substrate provided separately.
However, there is a demand for reducing the size of devices in the industry, and the miniaturization of unit wiring racks has led to a need for miniaturization of panel circuit boards as well. Since unit wiring racks and circuit boards are standardized, if the conventional connector terminal sizes and inter-terminal distance are used, there will be extremely limited space on the edges of the circuit boards on which the connectors are mounted, requiring the number of electrical terminals to be decreased. For this reason, it is desirable to be able to support more electrical terminals in the limited space on the edges of the circuit boards.
FIG. 14 is an exploded perspective view of a circuit board assembly showing a method for attaching a connector of the same type as that shown in FIG. 13 to a small circuit board using conventional art.
The panel circuit board 51 shown in FIG. 14 comprises a connector body 53 having a housing portion 513 for housing electrical terminals 52 for connection to predetermined wires on the circuit board 55, and a base portion 514 extending from the housing portion 513 and connected to the circuit board 55. Additionally, the panel circuit board 51 is constructed so that a panel 57 having an aperture portion 58 for passing the housing portion 513 and a frame body 518 having an aperture portion 58′ for passing the housing portion 513 and covering the housing portion 513 are attached as separate elements to the connector body 53 by means of predetermined screws, and to a cuboid block 511 to which an ejector 56 is attached.
The circuit board 55 and connector body 53 are attached by passing a pair of screws 520 (FIG. 14 shows only one of the screws) through a pair of through holes (not shown) provided in the circuit board 55 and a pair of through holes 526 (shown in FIG. 11) provided in the base portion 514, then fastening them with nuts or the like.
Additionally, the attachment between the ejector 56 and the circuit board 55 is achieved by passing a cam portion 529 of an ejector 56 through an aperture portion 59 in the front panel 57, aligning a turn axis hole 523 on the cam portion 529 with a through hole 524 in the cuboid block 511 and a through hole in the circuit board 55 (not shown), inserting a screw 521 into the connecting holes and fastening with a nut or the like. A tubular sleeve forming a spacer, not shown, is disposed between the cuboid block 511 and the nut, and the screw 521 is passed therein, so the ejector 56 is capable of turning.
As described above, conventional panel circuit boards 51 have a structure provided with two adjacent attachment portions, i.e. an attachment portion for attaching the circuit board 55 to the connector body 53, and an attachment portion for attaching the ejector 56 to the circuit board 55. They therefore make inefficient use of the space at the edges of the circuit board onto which a connector is to be mounted, and have a complicated mounting structure using many components.
Additionally, there has been a demand in the industry to support as many electrical terminals as possible in the limited space at the edges of circuit boards, while retaining the size and spacing of conventional electrical terminals.